Liquefaction of industrial gases is an important step which is used in the processing of almost all industrial gas separation and purification operations. Typically the industrial gas is liquefied by indirect heat exchange with a refrigerant. Such a system, while working well for providing refrigeration over a relatively small temperature range from ambient, is not as efficient when refrigeration over a large temperature range, such as from ambient to a cryogenic temperature, is required. One way this inefficiency has been addressed is to use a liquefaction process with multiple flow circuits wherein each circuit serves to reduce the temperature of the industrial gas over a portion of the range until the requisite cryogenic condensing temperature is reached. However, such multiple circuit industrial gas liquefiers may be complicated to operate.
Accordingly, it is an object of this invention to provide a single circuit liquefaction arrangement whereby industrial gas may be brought from ambient temperature to a cryogenic liquefaction temperature which operates with greater efficiency than heretofore available single circuit systems.